Debris observed by arthroscopy of the knee

In examination of 732 knee joints through the arthroscope since 1961, various types of debris were observed in 47. The debris was classified into four groups: precipitation of fibrin, degeneration and necrosis of villi, desquamation of articular cartilage, and metaplasia of villi. Diseases of the knee joint and their pathogenesis are discussed in the light of these findings.